Electrode, battery, and method for producing electrode

Abstract

An electrode to be used for a battery, the electrode including: a current collector, a first electrode layer arranged on the current collector, and a second electrode layer arranged on the first electrode layer, wherein the first electrode layer includes a first active material, and a first binder covering a surface of the first active material; the second electrode layer includes a second active material, and a second binder covering a surface of the second active material; and when C 1 (%) designates a coverage of the first binder with respect to the first active material, and C 2 (%) designates a coverage of the second binder with respect to the second active material, the C 1 is larger than the C 2 .

What is claimed is: 
     
         1 . An electrode to be used for a battery, the electrode comprising:
 a current collector, a first electrode layer arranged on the current collector, and a second electrode layer arranged on the first electrode layer, wherein   the first electrode layer includes a first active material, and a first binder covering a surface of the first active material;   the second electrode layer includes a second active material, and a second binder covering a surface of the second active material; and   when C 1  (%) designates a coverage of the first binder with respect to the first active material, and C 2  (%) designates a coverage of the second binder with respect to the second active material, the C 1  is larger than the C 2 .   
     
     
         2 . The electrode according to  claim 1 , wherein the C 1  is larger than 50%, and the C 2  is 50% or less. 
     
     
         3 . The electrode according to  claim 1 , wherein a difference between the C 1  and the C 2  is 30% or more. 
     
     
         4 . The electrode according to  claim 1 , wherein the first binder and the second binder are a fluorine-containing binder. 
     
     
         5 . The electrode according to  claim 1 , wherein the first binder and the second binder have the same composition. 
     
     
         6 . The electrode according to  claim 1 , wherein the first active material and the second active material are a lithium transition metal composite oxide. 
     
     
         7 . The electrode according to  claim 1 , wherein the first active material and the second active material have the same composition. 
     
     
         8 . The electrode according to  claim 1 , wherein
 the first electrode layer contains a first composite body in which the first binder and a first conductive material are dispersed on a surface of the first active material; and   the second electrode layer contains a second composite body in which the second binder and a second conductive material are dispersed on a surface of the second active material.   
     
     
         9 . A battery including a cathode, an anode, and an electrolyte layer arranged between the cathode and the anode, wherein
 at least one of the cathode and the anode is the electrode according to  claim 1 .   
     
     
         10 . The battery according to  claim 9 , wherein the battery is a lithium ion battery. 
     
     
         11 . A method for producing an electrode to be used for a battery, the method comprising:
 a first layer forming step of forming a first electrode layer on a current collector, using a first electrode mixture containing a first active material and a first binder covering a surface of the first active material, by a dry method; and   a second layer forming step of forming a second electrode layer on the first electrode layer, using a second electrode mixture containing a second active material and a second binder covering a surface of the second active material, by a dry method; and   when C 1  (%) designates a coverage of the first binder with respect to the first active material, and C 2  (%) designates a coverage of the second binder with respect to the second active material, the C 1  is larger than the C 2 .